Currently, the power network lacks vast communication capabilities, whereas the smart grid infrastructure relies on smart sensors and sophisticated communication technologies to operate. In addition, traditional power systems may not only require changes in order to upgrade their capacity, but they will require a considerable amount of instrumentation to monitor and control the reliable operation of the power system. Thus, the intelligent monitoring and control allowed by modern Information and Communication Technologies (ICT) have become of great importance in terms of achieving the fundamental purpose of the smart grid. However, failures of ICT can, therefore, affect the Gridâs reliability, so quantifying the risk involved with ICT failures, their functionality and implementation should be more specifically defined; this is primarily due to the vast diversity of ICT applications. To this end, the main objective of this thesis is to identify the impact of ICT failures using two different approaches within the smart grid. (1) Through ICT component unavailability and (2) through ICT inaccurate measurements. The inclusion of ICT within the power network is employed, within the implementation of Flexible AC Transmission Systems (i.e. FACTS-ICT) and Time-Varying Line Rating (i.e. TVLR-ICT) systems (often referred to as dynamic line rating equipment) to maximise the ampacities of the existing transmission and distribution networks, by increasing their power transfer capabilities. In particular, this thesis is based on a modified sequential Monte Carlo (SMC) modelling approach that integrates the TVLR-ICT (indirect and direct systems) and FACTS-ICT capabilities within the overhead lines and substations of the network operating states. This approach allows quantification of the increased network risk associated with such implementation. The proposed method is implemented on the IEEE 14-Bus system, which represents a distribution network, and IEEE RTS-96 which provides a transmission network, equivalent to multiple types of generation connected to it. Both networks are further modified to permit the implementation of both smart grid technologies. New performance indices are developed to evaluate the contribution of smart technologies to power network reliability, as well as to capture the stochastic nature of component failures following chronological trends. The reliability studies show that the impact of ICT failures on network reliability is mainly related to quality, and therefore the performance of the ICT implemented (i.e. ICT reliability). When FACTS and TVLR systems possess an identical level of ICT reliability, FACTS-ICT failures on transmission networks provoke twice as much increase in expected energy not supplied (EENS) than TVLR-ICT failures for a level of network loading up to 2.0pu (evenly increased in active and reactive power for generation and demand). This is contrary to the case of the distribution network, which is significantly more affected by TVLR-ICT failures, causing more than five times EENS in a network operating up to 1.5pu. Nevertheless, the risks and benefits of FACTS and TVLR smart technologies along with their ICT performances on power network reliability are investigated and quantified, and therefore the effect of their ICT failures can be better controlled and alleviated, shaping utility decisions about future options towards increased network adequacy and flexibility.